Air quality comparison · Mongolia, 541 km apart
Choibalsan vs Nalayh Air quality index (AQI) today
Choibalsan has cleaner air than Nalayh right now: AQI 11 (Good) against 25 (Good).
Both sit in the same EPA band, so the health advice is the same for each today. Over the past 7 days, on modeled daily averages, Choibalsan averaged AQI 23 against 36, and it was the cleaner of the two on 6 of those days. Nalayh has lost more forest since 2001. Choibalsan has more tree cover.
Mongolia
AQI 11
Good
Cleaner right now
- PM2.5
- 2.6 µg/m³
- Main pollutant
- PM2.5
- Source
- Model estimate
- Reading
- Nov 11, 18:00 local
Mongolia
AQI 25
Good
Cleaner right now
- PM2.5
- 6 µg/m³
- Main pollutant
- PM2.5
- Source
- Model estimate
- Reading
- Nov 11, 17:00 local
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Choibalsan11Nalayh25
Head to head
Choibalsan vs Nalayh at a glance
Choibalsan is ahead on 6 of 6 measures, and Nalayh on 0. The better figure in each row is marked.
| Choibalsan | Nalayh | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 11 (better) | 25 |
| PM2.5Fine particles, µg/m³. | 2.6 (better) | 6 |
| Past week's averageUS AQI, 7 days. | 23 (better) | 36 |
| Forest lost since 2001Within 10 km of the center. | under 1 ha (better) | 172 ha |
| Tree coverWithin 2 km of the center. | 2.7% (better) | 0.0% |
| Trees still neededTo reach a healthy canopy. | 85.3K (better) | 94.2K |
Air quality today
What is the air like in Choibalsan and Nalayh right now?
Choibalsan has cleaner air than Nalayh right now: AQI 11 (Good) against 25 (Good). PM2.5 is setting the index in both.
Both readings are model estimates, with no ground station close enough to either.
ChoibalsanNalayh
Concentrations at the same moment as the index above, for the pollutants both places report. Lower is better. The dark marks on the PM2.5 and PM10 rows show the WHO's 24-hour guidelines (15 and 45 µg/m³).
Choibalsan: Model estimate · no ground station nearby. Data: Open-Meteo / CAMS, US EPA index.
Nalayh: Model estimate · no ground station nearby. Data: Open-Meteo / CAMS, US EPA index.
The past week
Which had cleaner air over the past 7 days?
Over the past 7 days, on modeled daily averages, Choibalsan averaged AQI 23 against 36, and it was the cleaner of the two on 6 of those days. A single reading can catch a city on a bad afternoon; the week says whether it was the weather or the place.
- Cleaner days
- Choibalsan6Nalayh1
- Average AQI
- Choibalsan23Nalayh36
- Worst day, AQI
- Choibalsan51Nalayh53
The daily numbers (7 days)
| Day | Choibalsan | Nalayh |
|---|---|---|
| Nov 5 | 30 | 39 |
| Nov 6 | 15 | 27 |
| Nov 7 | 29 | 53 |
| Nov 8 | 51 | 41 |
| Nov 9 | 18 | 28 |
| Nov 10 | 12 | 21 |
| Nov 11 | 6 | 40 |
Daily averages from the CAMS atmospheric model for both places, so the week compares like with like. They can differ from today's reading at the top of the page wherever that comes from a ground station.
What it means today
Is it safe to go outside in Choibalsan and Nalayh today?
Air quality is satisfactory for everyone. Both are in the same EPA band today (Good), so the advice is the same.
Exercise outdoors
A good day to be active outside.
Windows
Open them to air the house.
Masks
Not needed.
Air purifier
Not needed.
Against everywhere else
How do Choibalsan and Nalayh compare with the rest of the world?
Right now Choibalsan's air is cleaner than 96% of the 5,420 places Airleaf tracks, and Nalayh's is cleaner than 85%. Within Mongolia, that is 75% and 25% of its 5 measured places.
Cleaner air than…
- Choibalsan
- Beats 96%
- Nalayh
- Beats 85%
More tree cover than…
- Choibalsan
- Beats 6%
- Nalayh
- Beats 0%
Includes model estimates as well as station readings, so it can differ from our most polluted and cleanest air rankings, which use station readings only.
Deforestation · 2001–2025
Which has lost more forest, Choibalsan or Nalayh?
Nalayh has lost more: about 172 ha of forest within 10 km of its center from 2001 to 2025, against under 1 ha around Choibalsan. under 1 ha of that was cleared for good, for farms, mines or towns.
Measured within 10 km of each center, from the yearly satellite maps of forest loss: a wider circle than the one for tree cover, because forest is usually lost at a city's edges.
Worst year: 2002, with under 1 ha lost.
Worst year: 2001, with 92 ha lost.
| Choibalsan | Nalayh | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | under 1 ha (better) | 172 ha |
| Cleared for goodTurned into farms, mines or towns. | under 1 ha (better) | under 1 ha |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Not classified | Wildfires (91%) |
Satellite timelapses
Watch both change, year by year
A clear satellite photo a year of the land around each city. Press play, turn on the forest cleared since the first year, or drag the before and after.
Choibalsan
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Nalayh
2017: satellite photo from June 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Choibalsan or Nalayh?
Choibalsan has more tree cover: 2.7% of the land within 2 km of its center against 0.0% around Nalayh, or about 8,440 trees against 0.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Choibalsan | Nalayh | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 8.4K (better) | 0 |
| Trees still neededTo reach the target. Fewer is better. | 85.3K (better) | 94.2K |
| CO₂ absorbed each yearBy the trees already standing. | 186K kg (better) | 0 kg |
Tree cover on the satellite image
The same 2 km radius around each center, with the tree cover the satellite found marked on it.
Reading these numbers
How this comparison is made
Air quality index
The US EPA index, computed from current pollutant concentrations: ground stations where a place has them nearby, and the CAMS atmospheric model everywhere else. It moves hour to hour, so it is a snapshot rather than a verdict on either place. The guideline marks are from the WHO's 2021 air quality guidelines.
Trees and forest
Tree cover is the share of ground under canopy within 2 km of each center, read from Sentinel-2 satellite imagery at 10 m detail. It measures that circle, not the whole municipality, which is what makes the two comparable. Forest loss comes from the University of Maryland's Global Forest Change maps.
More on the method on the About Airleaf page.
Frequently asked
Choibalsan vs Nalayh: your questions answered
Is Choibalsan cleaner than Nalayh?
On air quality, yes, right now: Choibalsan reads AQI 11 against 25, a gap of 14 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. Over the past 7 days, on modeled daily averages, Choibalsan averaged AQI 23 against 36, and it was the cleaner of the two on 6 of those days.
Is it safe to exercise outdoors in Choibalsan and Nalayh today?
The advice is the same for both today. Air quality is satisfactory for everyone. Choibalsan reads AQI 11 and Nalayh reads AQI 25.
Which has lost more forest, Choibalsan or Nalayh?
Nalayh has lost more: about 172 ha of forest within 10 km of its center from 2001 to 2025, against under 1 ha around Choibalsan. under 1 ha of that was cleared for good, for farms, mines or towns.
Which has more trees, Choibalsan or Nalayh?
Choibalsan has more tree cover: 2.7% of the land within 2 km of its center against 0.0% around Nalayh, or about 8,440 trees against 0. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Choibalsan and Nalayh need?
Choibalsan needs about 85,337 more to reach its canopy target of 30%, and Nalayh about 94,248 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Choibalsan and Nalayh measured the same way?
The method is the same: the US EPA index for air, and Sentinel-2 satellite imagery at 10 m detail over an identical radius for trees. Both readings are model estimates, with no ground station close enough to either. Nothing is adjusted for population, city limits or climate.
How often does the Choibalsan vs Nalayh comparison update?
The air readings refresh about once an hour, and each reading's local time is shown at the top of the page. Tree cover comes from the latest clear satellite image of each area (Sep 19, 2026 and Sep 15, 2026), and the forest figures are published yearly.
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